The present invention pertains to the art of dispensing fluid products and, more particularly, to dispensing of fluid products such as soaps in the medical field.
In the packaging of various fluid products ranging from personal care products such as shampoo, conditioner, toothpaste, lotion, or soap, to food products such as ketchup and mustard, many different packaging designs have evolved. Some increasingly popular packaging designs include automatically operating self-sealing valves which open when a container is squeezed and closed when pressure is released from the container. These types of self-sealing closures are easy to use and provide means for positively closing the valve to prevent accidental dispensing of the product. A wide variety of these automatically operating closures are available. However, many of the self-sealing valve designs suffer from the disadvantages of being difficult to control and/or allowing drips to occur after the pressure to the container has been removed.
The flexible, self-sealing dispensing valves which are currently available for dispensing fluid products such as soaps and shampoos generally include a resiliently deformable valve portion having a discharge orifice which may be formed in a variety of shapes such as a slit or a cross. Deformable valves having a concave shape in the closed position have been found to successfully eliminate dripping. Some examples of these types of valves are illustrated in U.S. Pat. Nos. 4,728,006 and 4,991,745. To use these self-sealing type valves, a flexible container is manually deformed causing the pressure of the fluid product on the valve to deform the flexible valve outward and discharge the fluid product through the dispensing opening in the valve. Once the manual pressure on the flexible container has been removed, the self-sealing valve returns past its original sealed position and opens inwardly allowing air to be sucked back into the container to return the flexible container to an equilibrium position for further dispensing.
In the medical field, various fluid products such as soap which are dispensed must be maintained in a sterile condition. However, with the known self-sealing valves, ambient air flows back into the container of fluid product through the valve after the fluid product is dispensed. This creates a situation in which harmful bacteria or other contaminants present in the air can be introduced to the fluid product and be spread by use of the product. Therefore, in the medical field, it is desirable to provide a dispensing valve which prevents ambient air from entering the container through the valve.